Mercator projection distort size, especially Greenland and Africa

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Everydata: The Misinformation Hidden in the Little Data You Consume Every Day by John H. Johnson

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Even worse, the distortion wasn’t equal; the farther an object is from the equator, the more distorted it appears. In practical terms, this means that objects closer to the poles appear to be much larger, relatively speaking, than objects closer to the equator. This artifact is commonly known (to cartographers, at least) as “the Greenland problem” because, on a Mercator map, it looks like Greenland is about the same size as Africa. But it’s not. In fact, it’s not even close. If you compare the two based on land area, Africa is approximately 14 times larger than Greenland. But Africa is on the equator (hence, less distortion) while Greenland sits largely above the Arctic Circle, and therefore looks much larger on a Mercator map than it really is.2 So what’s the problem?


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Maphead: Charting the Wide, Weird World of Geography Wonks by Ken Jennings

Apollo 11, Asperger Syndrome, augmented reality, Bartolomé de las Casas, Berlin Wall, Boris Johnson, British Empire, clean water, David Brooks, digital map, don't be evil, dumpster diving, Eratosthenes, game design, Google Earth, GPS: selective availability, helicopter parent, hive mind, index card, John Harrison: Longitude, John Snow's cholera map, Mercator projection, Mercator projection distort size, especially Greenland and Africa, Mikhail Gorbachev, New Journalism, openstreetmap, place-making, Ronald Reagan, Saturday Night Live, Skype, Stewart Brand, Tacoma Narrows Bridge, three-masted sailing ship, traveling salesman, urban planning

.* The problem is that this kind of projection inflates the polar regions way out of proportion—in fact, on such a map, the poles can never even be drawn, because they’re an infinite distance from the Equator.† Mercator maps were still used everywhere when I was growing up—classrooms, nightly newscasts, stamps, government briefing rooms—and so my generation grew up thinking that Greenland was bigger than Africa, since Greenland is oversized fourteenfold on Mercator maps. Of course, all map projections have to fudge somewhere, whether on area or on direction. Imagine trying to flatten an orange peel onto a flat surface, and as it tears and scrunches, you’ll see the problem: something’s got to give.* But the Mercator map stayed so popular in the West for so long, at least in part, because of how helpful its particular distortions were.


pages: 306 words: 79,537

Prisoners of Geography: Ten Maps That Explain Everything About the World (Politics of Place) by Tim Marshall

9 dash line, Admiral Zheng, anti-communist, Berlin Wall, British Empire, California gold rush, Charlie Hebdo massacre, colonial rule, cuban missile crisis, Deng Xiaoping, drone strike, European colonialism, facts on the ground, failed state, Fall of the Berlin Wall, Hans Island, Kickstarter, LNG terminal, market fragmentation, megacity, Mercator projection distort size, especially Greenland and Africa, Mikhail Gorbachev, military-industrial complex, Monroe Doctrine, Nelson Mandela, oil shale / tar sands, Scramble for Africa, South China Sea, Suez canal 1869, Suez crisis 1956, trade route, transcontinental railway, Transnistria, UNCLOS, UNCLOS, zero-sum game

If you look at a world map and mentally glue Alaska onto California, then turn the United States on its head, it appears as if it would roughly fit into Africa with a few gaps here and there. In fact, Africa is three times larger than the United States. Look again at the standard Mercator map and you see that Greenland appears to be the same size as Africa, and yet Africa is actually fourteen times the size of Greenland! You could fit the United States, Greenland, India, China, Spain, France, Germany, and the UK into Africa and still have room for most of Eastern Europe. We know Africa is a massive landmass, but the maps rarely tell us how massive.


pages: 665 words: 159,350

Shape: The Hidden Geometry of Information, Biology, Strategy, Democracy, and Everything Else by Jordan Ellenberg

Albert Einstein, AlphaGo, Andrew Wiles, autonomous vehicles, British Empire, Brownian motion, Charles Babbage, Claude Shannon: information theory, computer age, coronavirus, COVID-19, deep learning, DeepMind, Donald Knuth, Donald Trump, double entry bookkeeping, East Village, Edmond Halley, Edward Jenner, Elliott wave, Erdős number, facts on the ground, Fellow of the Royal Society, Geoffrey Hinton, germ theory of disease, global pandemic, government statistician, GPT-3, greed is good, Henri Poincaré, index card, index fund, Isaac Newton, Johannes Kepler, John Conway, John Nash: game theory, John Snow's cholera map, Louis Bachelier, machine translation, Mercator projection, Mercator projection distort size, especially Greenland and Africa, Milgram experiment, multi-armed bandit, Nate Silver, OpenAI, Paul Erdős, pets.com, pez dispenser, probability theory / Blaise Pascal / Pierre de Fermat, Ralph Nelson Elliott, random walk, Rubik’s Cube, self-driving car, side hustle, Snapchat, social distancing, social graph, transcontinental railway, urban renewal

Indeed, Mercator cut his off at parallels well short of the poles to avoid the painfully apparent Arctic and Antarctic distortions. Latitude lines near the poles get farther and farther apart on the map, while in real life they’re separated by the same distance. That makes things in the polar region look bigger than they really are. In the Mercator projection, there’s as much Greenland as there is Africa. In reality, Africa is fourteen times bigger. Couldn’t there be a better projection? You might want great circles to show up as straight lines (a gnomonic projection) and you might want the relative areas of geographic objects to match real life (an authalic projection) and you might want the projection to get angles right (a conformal projection, of which Mercator’s is one).